Differential with pinion bearings supported on input yoke

ABSTRACT

A differential having pinion bearings supported on the input yoke is provided. The differential includes a housing having an opening through which a pinion shaft extends. The input yoke is disposed about a portion of the pinion shaft and one or both pinion bearing sets are then disposed about the input yoke. This configuration reduces pinion standout and allows for installation of a pre-assembled bearing pack (i.e., without spacers or shims), but does not reduce the length of the splines on the input yoke or bearing capacity.

[0001] This application is a continuation-in-part application of U.S.patent application Ser. No. 10/033,253 filed Oct. 25, 2001.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to vehicle differentials and, inparticular, to the location and support of pinion bearings within adifferential.

[0004] 2. Discussion of Related Art

[0005] Differentials are used in vehicles to allow wheels mounted oneither side of a vehicle axle to rotate at different speeds. Aconventional differential includes a series of gears disposed within adifferential housing that transmit torque from a power input shaft toaxle half shafts supporting the wheels. One of these gears is a piniongear. The differential housing defines an opening through which a pinionshaft extends to support the pinion gear. Bearings are disposed withinthe opening to allow the pinion shaft to rotate relative to the housing.An input yoke is coupled to the pinion shaft and to the power inputshaft to transmit torque from the power input shaft to the pinion shaft.

[0006] Conventional differentials have several problems. First, thepinion shaft and input yoke extend outwardly from the differentialhousing for a relatively large distance (“pinion standout”). As aresult, the differential requires additional space and the mounting ofvehicle suspension components and other vehicle components is made fordifficult. Second, installation and proper placement of the pinionbearings often require the use of spacers or shims during assemblythereby increasing assembly time.

[0007] There is thus a need for a differential for a vehicle that willminimize or eliminate one or more of the above-mentioned deficiencies.

SUMMARY OF THE INVENTION

[0008] The present invention provides a differential for a vehicle.

[0009] A differential in accordance with one embodiment of the presentinvention includes a differential housing that defines a first opening.The differential also includes a pinion shaft disposed within the firstopening and configured for rotation about an axis extending through thefirst opening. The differential further includes an input yoke disposedabout a least a portion of the pinion shaft. Finally, the differentialincludes a first bearing set disposed about the input yoke. Thedifferential may also include a second bearing set axially spaced fromthe first bearing set and also disposed about the input yoke.

[0010] A differential in accordance with another embodiment of thepresent invention includes differential housing defining a first openingand a pinion shaft disposed within the first opening and configured forrotation about an axis extending through the first opening. Thedifferential further includes a pinion gear mounted on the pinion shaftand an input yoke disposed about a portion of the pinion shaft. Thedifferential further includes a first bearing set disposed about theinput yoke and having a bearing cone in engagement with the input yokeand a second bearing set axially spaced from the first bearing set andhaving a bearing cone in engagement with the pinion shaft.

[0011] A differential in accordance with the present invention hasseveral advantages as compared to conventional vehicle differentials.The location of the bearing set(s) on the input yoke shortens theoverall length of the pinion shaft while still allowing sufficientengagement between the pinion shaft and input yoke. As a result, pinionstandout is reduced. The location of the bearing sets further allows theuse of a preassembled bearing pack comprised of the bearing sets and acarrier for the bearing sets for proper positioning of the bearing setswithin the differential housing opening. As a result, spacers and/orshims are not required and differential assembly time may besignificantly reduced.

[0012] These and other features and objects of this invention willbecome apparent to one skilled in the art from the following detaileddescription and the accompanying drawings illustrating features of thisinvention by way of example.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a sectional view of a differential in accordance withone embodiment of the present invention.

[0014]FIG. 2 is a partial sectional view of a differential in accordancewith another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015] Referring now to the drawings wherein like reference numerals areused to identify identical components in the various views, FIG. 1illustrates a differential 10 in accordance with one embodiment of thepresent invention. Differential 10 is provided to allow wheels (notshown) disposed on either side of the vehicle, and supported on axlehalf shafts (not shown) extending from differential 10, to rotate atdifferent speeds. Differential 10 is particularly adapted for use in aheavy truck. It should be understood, however, that the presentinvention is not limited to use in heavy trucks and may be used in awide variety of vehicles. Differential 10 may include a housing 12, adifferential gear assembly 14, a pinion shaft 16, an input yoke 18, acarrier 20, and bearing sets 22, 24.

[0016] Housing 12 provides structural support for the other componentsof differential 10. Housing 12 also protects the other components ofdifferential 10 from foreign objects and elements. Housing 12 may bemade from conventional metals and metal alloys such as steel and mayinclude multiple members 26, 28, 30 that are sized relative tocomponents of differential 10 and coupled together using conventionalfasteners (not shown). Member 26 of housing may define an opening 34 ata forward end. Opening 34 may be centered about an axis 36 extendingthrough pinion shaft 16.

[0017] Differential gear assembly 14 is provided to allow the wheelssupported on either side of the vehicle to rotate at different speeds.Assembly 14 may include a pinion gear 38, a ring gear 40, and aconventional bevel gear set (not shown) disposed within a differentialcarrier (not shown).

[0018] Pinion gear 38 is provided to transfer torque from pinion shaft16 to ring gear 40. Pinion gear 38 may be made from conventional metalsand metal alloys and may comprise a hypoid gear. Gear 38 rotates aboutaxis 36. Gear 38 is disposed about shaft 165 and may be integraltherewith or mounted thereto using a conventional spline connection orin other ways customary in the art. Gear 38 may also include a pilotportion 42 extending rearwardly that is supported for rotation bybearings 44 disposed in a pilot web 46 of housing member 26.

[0019] Ring gear 40 is provided to transfer torque from pinion gear 38to the bevel gear set and is conventional in the art. Ring gear 40 mayalso be made from conventional metals and metal alloys and may alsocomprise a hypoid gear. Gear 40 is affixed to the carrier or may beintegral therewith.

[0020] The bevel gear set (not shown) is provided to transfer torquefrom ring gear 40 to the axle half shafts supporting the vehicle wheels.The bevel gear set is conventional in the art.

[0021] Pinion shaft 16 is provided to transmit power from a power inputshaft (not shown) to pinion gear 38 and is conventional in the art.Pinion shaft 16 may include a first portion 48 having a first diameter,a second portion 50 having a second diameter greater than the firstdiameter and a tapered portion 52 joining portions 48, 50. Pinion shaft16 may include a plurality of splines 54 extending axially along portion48 from a forward end of shaft 16 to tapered portion 52. Pinion shaft 16may also include a threaded shank 56 extending from a forward end ofshaft 16 and integral therewith.

[0022] Input yoke 18 is provided to transmit power from a power inputshaft (not shown) to pinion shaft 16. Yoke 18 may be coupled to thepower input shaft through a conventional universal joint (not shown) andis configured for rotation about axis 36. Yoke 18 includes a generallycylindrical body 58 with a circular flange 60 radiating outwardly frombody 58 at a forward end of body 58. Body 58 defines a bore 62 sized toreceive pinion shaft 16 and extends axially along shaft 16 to therearward end of shaft 16 such that one axial end of yoke 18 is proximatepinion gear 38. Yoke 18 may include a plurality of splines 64 configuredfor engagement with splines 54 of pinion shaft 16. In accordance withthe present invention, splines 64 may be disposed radially inwardly ofbearing set 22. Yoke 18 may be retained on shaft 16 by a nut 66 and awasher (not shown) disposed about stud 56 of shaft 16.

[0023] Carrier 20 is provided to position and support bearing sets 22,24 within opening 34 of housing 12 and may be made from conventionalmetals or metal alloys. Carrier 20 is generally cylindrical in shape andis sized to be received within opening 34 of housing 12. Carrier 20includes a radially outwardly extending flange 68 at a forward end thatabuts a shoulder 70 formed in housing 12 upon installation of carrier 20within opening 34. Carrier 20 may be held within opening 34 by a cap 72that is fastened to member 26 of housing 12 using conventional fasteners(not shown). Carrier 20 is disposed about axis 36 and defines a bore 74configured to receive bearing sets 22, 24. A radially inwardly extendingflange 76 within bore 74 defines a pair of shoulders 78, 80 and helpsenable proper positioning of bearing sets 22, 24 without the need forspacers or shims.

[0024] Bearings sets 22, 24 are provided to allow rotation of input yoke18 and pinion shaft 16 relative to carrier 20 and housing 12. Bearingsets 22, 24 are conventional in the art and may comprise tapered rollerbearings. Each bearing set 22, 24 includes a cone 82, 84, respectively,defining an inner bearing race and a cup 86, 88, respectively, definingan outer bearing race. Cone 82 of bearing set 22 is in engagement with ashoulder 90 defined in input yoke 18 and cup 86 of bearing set 22 is inengagement with shoulder 78 of carrier 20. Cone 84 of bearing set 24 isin engagement with pinion gear 38 while cup 88 of bearing set 24 is inengagement with shoulder 80 of carrier 20. In accordance with thepresent invention, bearing sets 22, 24 are disposed about input yoke 18between yoke 18 and carrier 20. In particular, cones 82, 84 aresupported on body 58 of yoke 18. The relative location of bearing sets22, 24 and input yoke 18 result in a significant improvement as comparedto conventional differentials. In particular, yoke 18 is moved forwardin differential 10 thereby enabling a reduction in pinion standout, butstill allowing yoke 18 to maintain proper engagement with pinion shaft16 because the lengths of splines 54, 64 are not reduced. Further,bearing capacity remains the same in the inventive differential.

[0025] Referring now to FIG. 2, a differential 110 in accordance withanother embodiment of the present invention is illustrated. Differential110 includes may include many components that are substantially similarto components found in differential 10 described hereinabove including,for example: (i) a housing 112 having a member 114 defining an opening116 at a forward end centered about an axis 118; (ii) a differentialgear assembly including a pinion gear 120; and (iii) a pinion shaft 122configured for rotation about axis 118 and having a plurality of axiallyextending splines 124. Accordingly, additional information regardingthese components may be obtained hereinabove. Differential 110 mayfurther includes an input yoke 126, a spacer 128, a carrier 130, andbearing sets 132, 134.

[0026] Input yoke 126 is provided to transmit power from a power inputshaft (not shown) to pinion shaft 122. Yoke 126 may be coupled to thepower input shaft through a conventional universal joint (not shown) andis configured for rotation about axis 118. Yoke 126 includes a generallycylindrical body 136 with a circular flange 138 radiating outwardly frombody 136 at a forward end of body 136. Body 136 defines a bore 140 sizedto receive pinion shaft 122 and extends axially along shaft 122,terminating at a point intermediate the forward and rearward ends ofpinion shaft 122. Yoke 126 may include a plurality of splines 142configured for engagement with splines 124 of pinion shaft 122. Inaccordance with the present invention, splines 124 may be disposedradially inwardly of bearing set 132. Yoke 126 may be retained on shaft122 by a nut (not shown) and a washer (not shown) disposed about athreaded stud 144 extending from the forward end of shaft 122. Yoke 126has a stepped outer diameter defining a shoulder 146 for a purposedescribed hereinbelow.

[0027] Spacer 128 is provided to set bearing preload and maintain theposition of bearing sets 132, 134. Spacer 128 is disposed betweenbearing sets 132, 134 and also between input yoke 126 and bearing set134. Spacer 128 has a central bore configured to receive pinion shaft122 and may have a stepped outer diameter as shown in the illustratedembodiment. Together with yoke 126, the forward end of spacer 128defines a shoulder 148 for a purpose described hereinbelow. Similarly,the rearward end of spacer 128, together with pinion shaft 122, definesa shoulder 150 for a purpose described hereinbelow.

[0028] Carrier 130 is provided to position and support bearing sets 132,134 within opening 116 of housing 112 and may be made from conventionalmetals or metal alloys. Carrier 130 is generally cylindrical in shapeand is sized to be received within opening 116 of housing 112. Carrier130 may be held within opening 116 by a cap (not shown) that is fastenedto member 114 of housing 112 using conventional fasteners (not shown) asdiscussed hereinabove with reference to FIG. 1. Carrier 130 is disposedabout axis 118 and defines a bore 152 configured to receive bearing sets132, 134.

[0029] Bearings set 132, 134 are provided to allow rotation of inputyoke 126 and pinion shaft 122 relative to carrier 130 and housing 112.Bearing sets 132, 134 are conventional in the art and may comprisetapered roller bearings. Each bearing set 132, 134 includes a cone 154,156, respectively, defining an inner bearing race and a cup 158, 160,respectively, defining an outer bearing race. Cone 154 of bearing set132 is disposed and retained between shoulders 146, 148, and may be inengagement with one or both of shoulders 146, 148. Cone 156 of bearingset 134 is disposed and retained between shoulder 150 and pinion gear120 and may be in engagement with one or both of shoulder 150 and piniongear 120. In accordance with the present invention, bearing set 132 isdisposed about input yoke 126 between yoke 126 and carrier 130. Inparticular, cone 154 is supported on body 136 of yoke 126. The relativelocations of bearing set 132 and input yoke 126 again results in asignificant improvement as compared to conventional differentials. Inparticular, yoke 126 is moved forward in differential 110 therebyenabling a reduction in pinion standout, but still allowing yoke 126 tomaintain proper engagement with pinion shaft 122 because the lengths ofsplines 142, 124, respectively, is not reduced. Further, bearingcapacity remains the same in the inventive differential.

[0030] While the invention has been particularly shown and describedwith reference to the preferred embodiments thereof, it is wellunderstood by those skilled in the art that various changes andmodifications can be made in the invention without departing from thespirit and scope of the invention.

We claim:
 1. A differential for a vehicle, comprising: a differentialhousing defining a first opening; a pinion shaft disposed within saidfirst opening and configured for rotation about an axis extendingthrough said first opening; a pinion gear mounted on said pinion shaft;an input yoke disposed about a portion of said pinion shaft; a firstbearing set disposed about said input yoke and having a bearing cone inengagement with said input yoke; and, a second bearing set axiallyspaced from said first bearing set and having a bearing cone inengagement with said pinion shaft.
 2. The differential of claim 1,further comprising a spacer disposed between said input yoke and saidbearing cone of said second bearing set.
 3. The differential of claim 2wherein said bearing cone of said first bearing set is disposed betweenopposed shoulders formed in said input yoke and said spacer.
 4. Thedifferential of claim 2 wherein said bearing cone of said second bearingset is retained between said spacer and said pinion gear.
 5. Thedifferential of claim 4 wherein said bearing cone of said second bearingset engages said spacer and said pinion gear.
 6. The differential ofclaim 1 wherein said input yoke includes a plurality of splinesconfigured for engagement with a corresponding plurality of splines onsaid pinion shaft, said plurality of splines on said input yoke disposedradially inwardly of said first bearing set.
 7. The differential ofclaim 1, further comprising a carrier disposed within said opening,radially outwardly of said input yoke.
 8. The differential of claim 7wherein said first bearing set is disposed between said carrier and saidinput yoke.